A three-judge panel of the 9th U.S. Circuit Court of Appeals will hear arguments Monday on the constitutionality of the city's ban on aerial advertising.

The Center for Bio-Ethical Reform, a California-based anti-abortion group, sued the city in 2003 after the city prohibited the group from using an airplane to tow banners that show graphic photographs of aborted fetuses.

The city law that bans aerial advertising has been in place for 33 years. But the group said the ban violated its constitutional right to free speech.

Last November, U.S. District Judge David Ezra ruled that the city ordinance was constitutional. Ezra said that airspace is a nonpublic forum and that restrictions on speech "need only be reasonable and viewpoint-neutral."

The Center for Bio-Ethical Reform appealed Ezra's ruling, insisting that the airspace above O'ahu's parks and beaches is a public forum where the group should be allowed to exercise its constitutional right to free speech.

Robert Muise, the group's lead attorney based in Michigan, could not be reached for comment yesterday. Robert Matsumoto, an attorney representing the group here, said the center also is expected to argue Monday that federal laws supersede state or local laws.

"It'll be a pre-emption, meaning that the Federal Aviation Administration has authority over any state law that would try to block or impede the banner from being flown," Matsumoto said.

"Pre-emption is a fancy term meaning that the federal law is superior to state law, especially when it comes to the First Amendment."

City attorneys could not be reached for comment yesterday. But they argued last year that the law is constitutional because it is "content-neutral" and prohibits any message from appearing in the skies above O'ahu. City attorneys also said airspace is heavily regulated and does not qualify as a public forum.

Reach Curtis Lum at culum@honoluluadvertiser.com.